JP2006326971A - Weatherable resin film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a weatherable resin film which is suitable, for example, for a decorative film, a film for a solar battery, etc., as a film for an outdoor member owing to its high ultraviolet shielding effect and its chalking phenomenon suppressing effect. <P>SOLUTION: In the weatherable resin film, a light-proof layer 1 containing ultraviolet absorbing metal oxide particles 0.1 μm or below in average particle size is formed on at least one side of a substrate resin film, and a light-proof layer 2 containing an organic ultraviolet absorber is formed on the surface layer of the light-proof layer 1. A laminated film is used preferably as the substrate resin film. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a resin film excellent in weather resistance. More specifically, the present invention relates to a weather resistant resin film suitably used for industrial material members and optical members excellent in long-term weather resistance, for example, decorative films and solar cell reflectors.

  Conventionally, as a means for suppressing photodegradation due to sunlight of a resin, a method of mixing an ultraviolet absorber into the resin or a method of applying an ultraviolet absorber to the surface layer of the resin is generally known. As ultraviolet absorbers, for example, organic absorbers such as benzophenone, benzotriazole, cinnamic acid derivatives and coumaric acid derivatives, and inorganic absorbers such as zinc oxide and titanium oxide are known. The selection of these ultraviolet absorbers is appropriately selected depending on the type of resin, exposure environment conditions, required weather resistance, and the like. In general, if the weather resistance is not sufficient, long-term exposure to ultraviolet rays will damage the optical properties of the resin film, or the mechanical strength and elongation will decrease, making it easy to break. When doing so, weather resistance was essential. In particular, a resin film containing amorphous polyester has a short weather resistance life and is required to have more effective weather resistance performance.

  However, the organic absorbent has a problem that the ultraviolet ray cutting efficiency is insufficient, and the ultraviolet ray absorbing ability is attenuated over a long period of time or is slightly yellowish. Moreover, since the ultraviolet absorber has a small amount of dissolution, the thickness of the binder must be increased. On the other hand, inorganic absorbers have high UV-cutting efficiency and do not have the above problems, but zinc oxide and titanium oxide themselves have high photocatalytic activity, so they absorb ultraviolet rays and generate radicals. There was a problem of deteriorating the resin. For example, when zinc oxide or titanium oxide is kneaded into the resin, this photocatalytic activity may promote deterioration of the resin by radicals generated by ultraviolet absorption, and rather deteriorate weather resistance.

  In addition, when these inorganic absorbents are finely dispersed in the coating material and coated on the base resin film, the base resin film does not deteriorate, but the coating resin deteriorates and the shape of the coating film can be maintained. Disappear. As a result, when exposed to ultraviolet rays and wind and rain over a long period of time, a so-called choking phenomenon occurs in which the metal oxide particles are exposed / dropped on the surface, resulting in a problem that transparency and weather resistance are greatly deteriorated.

  Therefore, as a countermeasure against the choking phenomenon in the prior art, a method using an inorganic binder obtained from a metal alkoxide or polysiloxane has been studied. However, an inorganic binder is low in flexibility and cracks when bent. May occur and the mechanical properties of the resin film may be greatly reduced.

Furthermore, as a countermeasure against the choking phenomenon, a part of the surface of the metal oxide particles is covered with a photo-inert inorganic substance, and thereby attempts to prevent the deterioration of the binder are widely performed (Patent Document 1 and Patent Document 2). reference). However, these proposals still have insufficient effects, and there is a problem that the dispersibility of the particles is lowered due to the inactivation of the surface and the transparency is impaired.
JP 2000-254518 A JP 2001-106993 A

  The object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a weather-resistant resin film having excellent long-term weather resistance and being colorless and transparent in the visible region.

  In order to solve the above problems, the weather resistant resin film of the present invention has the following constitution. That is, the weather-resistant resin film of the present invention has a light-resistant layer 1 containing metal oxide particles having an average particle size of 0.1 μm or less on at least one surface of a base resin film, and further its light resistance. The light-resistant layer 2 containing an organic ultraviolet absorber is provided on the surface layer of the layer 1.

According to a preferred embodiment of the weather resistant resin film of the present invention, a light stabilizer is further dispersed in the light resistant layer 1.
According to a preferred embodiment of the weather-resistant resin film of the present invention, the metal oxide particles having ultraviolet absorbing ability are any one of zinc oxide, titanium oxide, cerium oxide, titanium trioxide, and strontium titanate, or these. It is a mixture of
According to a preferred embodiment of the weather resistant resin film of the present invention, the base resin film has a structure in which 10 layers or more of layers made of resin A (layer A) and layers made of resin B (layer B) are alternately laminated. Or / and the base resin film is a laminated film having a structure in which layers made of a crystalline resin and layers made of an amorphous resin are alternately laminated.

According to a preferred embodiment of the weather resistant resin film of the present invention, the haze of the weather resistant resin film of the present invention is 10% or less.
According to a preferred embodiment of the weather resistant resin film of the present invention, the weather resistant resin film of the present invention has a reflectance of 30% or more for light in any part of the wavelength range of 250 to 2500 nm, and / or The reflectance with respect to light of at least a wavelength band of 420 to 780 nm is 40% or more.

  The weather-resistant resin film of the present invention is suitably used as a material for decorative films and solar cell reflectors.

  The weather-resistant resin film of the present invention has a light-resistant layer 1 containing metal oxide particles having an average particle size of 0.1 μm or less on at least one surface of a base resin film, and further the light-resistant layer 1 The light-resistant layer 2 containing an organic ultraviolet absorber is provided on the surface layer, and by doing so, the long-term weather resistance of the resin film can be improved while maintaining transparency.

  Hereinafter, embodiments of the weather resistant resin film of the present invention will be described in detail.

  The weather-resistant resin film of the present invention has a light-resistant layer 1 containing metal oxide particles having an average particle size of 0.1 μm or less on at least one surface of a base resin film, and further the light-resistant layer 1 The light-resistant layer 2 containing an organic ultraviolet absorber must be provided on the surface layer.

  In the present invention, the term “ultraviolet absorbing ability” refers to having an action of absorbing light in any part of a wavelength band of 340 nm to 390 nm. When the absorption of ultraviolet rays is on the shorter wavelength side than 340 nm, deterioration of the base resin film itself cannot be suppressed, and when it exceeds 390 nm, coloring occurs by absorbing visible light.

  As the metal oxide particles having ultraviolet absorbing ability of the present invention, a metal oxide having a semiconductor property having a band gap in the vicinity of 3.1 eV is suitable. Examples of such a metal oxide include zinc oxide, Titanium oxide, cerium oxide, tungsten trioxide, strontium titanate, and the like are applicable, and in the present invention, these are preferably used alone or in a mixture. Among these, zinc oxide and titanium oxide are relatively inexpensive and are preferably used. In particular, zinc oxide is superior in transparency because it has a higher absorption edge of ultraviolet rays of 380 nm and a lower refractive index than titanium oxide.

  These metal oxide particles are preferably coated on the surface with a substance that does not decompose due to catalytic activity, and examples of substances that do not decompose due to catalytic activity include oxides such as Al, Si, and Zr. By doing so, the catalytic activity of the metal oxide particles can be suppressed, and the choking phenomenon due to exposure to ultraviolet rays can be reduced.

In this invention, it is preferable that the quantity of the metal oxide particle contained in the light-resistant layer 1 apply | coated on at least one surface of a base resin film is 5 to 20 g per 1 m < ² > of base resin films. The amount of the metal oxide particles is more preferably 7 g or more and less than 20 g per m ² , and further preferably 10 g or more and less than 20 g per m ² . When the amount of the metal oxide particles is 5 g or more per 1 m ^{2 of} the film, an excellent ultraviolet shielding effect is exhibited. On the other hand, when the amount exceeds 20 g, the elongation of the weather resistant resin film is significantly reduced. It becomes brittle.

  In order to obtain a transparent appearance, it is necessary to reduce the scattering of particles in the visible light region. For that purpose, it is important to make the particle size sufficiently smaller than the wavelength of visible light, and in the present invention, it is necessary to make the average particle size of the metal oxide particles having ultraviolet absorbing ability 0.1 μm or less. . The average particle diameter of the metal oxide particles is more preferably 0.05 μm or less, and further preferably 0.03 μm or less. If the average particle size can be reduced as described above, a sufficiently transparent appearance can be obtained, and the ultraviolet ray shielding effect is increased by reducing the particle size. The lower limit of the average particle diameter is not particularly limited, but from the viewpoint of the surface energy of the particles, it is difficult to obtain a uniform dispersion of less than 0.01 μm, so the average particle diameter of industrially obtained particles is 0.01 μm or more.

In the present invention, by providing the light-resistant layer 2 containing the organic ultraviolet absorber on the surface layer of the light-resistant layer 1, the excitation reaction of the metal oxide particles in the light-resistant layer 1 is greatly suppressed, and as a result A resin film having excellent long-term weather resistance can be obtained.
The organic ultraviolet absorber in the present invention absorbs light in a part of a band of 360 to 390 nm mainly composed of an organic agent, and is particularly limited to a low molecular weight type or a high molecular weight type. Not. Moreover, the organic ultraviolet absorber may be in a state of being chemically bonded to the binder resin. Examples of the organic ultraviolet absorber include benzophenone-based, benzotriazole-based, salicylate-based, cyanoacrylate-based, oxanilide-based, salicylate-based, and acrylonitrile-based organic ultraviolet absorbers. Among these, benzotriazole-based organic ultraviolet absorbers are particularly preferred because of their high ultraviolet absorptance. Representative organic ultraviolet absorbers of the benzotriazole type include, for example, (2′hydroxyphenyl) benzotriazole, (2′hydroxy5′-methylphenyl) benzotriazole, and (2′hydroxy3 ′ tertiary butyl 5). '-Methylphenyl) 5-chlorobenzotriazole and the like can be used. In particular, (2′hydroxy 3 ′ tertiary butyl 5′-methylphenyl) 5 chlorobenzotriazole is preferably used because of its high ultraviolet absorption wavelength.

  The resin binder of the light-resistant layer 1 and the light-resistant layer 2 is preferably a resin having transparency. For example, polyester resin, acrylic resin, fluorine-based resin, silicon-based resin, melamine-based resin, vinyl chloride resin, vinyl Examples include butyral resins, cellulose resins, and polyamide resins. Among these, acrylic resins that are particularly inexpensive and excellent in light stability are preferable, and in this resin binder, metal oxide particles or organic ultraviolet absorbers are added. Can be used in finely dispersed form.

  The weight ratio of the metal oxide particles (metal oxide particles / resin binder) to the resin binder of the light-resistant layer 1 is preferably in the range of 0.4 to 1.55. The weight ratio of metal oxide particles is more preferably in the range of 1.9 to 1. When the weight ratio of the metal oxide particles to the resin binder exceeds 2.3, the thickness of the binder becomes very large, and problems such as curling may occur in the weather resistant resin film. Further, when the weight ratio of the metal oxide particles is less than 0.65, the dispersibility of the particles is lowered, and the transparency tends to be deteriorated.

  Moreover, it is preferable that the preferable weight ratio (organic ultraviolet absorber / resin binder) of the organic ultraviolet absorber with respect to the resin binder of the light-resistant layer 2 is in the range of 0.005 to 0.7. The preferred weight ratio when the UV absorber is chemically bonded to the binder resin is calculated as (UV absorbing group bonded to resin / resin binder), and the range is 0.005 to 0.00. A range of 3 is preferable.

  The coating thickness obtained by combining both the light-resistant layers 1 and 2 is generally in the range of 1 to 20 μm. The more preferable range of the coating film thickness is 3 to 16 μm, and the most preferable range is 5 to 12 μm. When the coating film thickness is larger than 20 μm, a problem occurs in transparency and film handling properties. When the coating film thickness is smaller than 1 μm, the weather resistance may be greatly lacked. The ratio of the coating thickness of the light-resistant layer 1 and the light-resistant layer 2 is not particularly limited, and sufficient long-term weather resistance can be exhibited as long as the amount of metal oxide particles and ultraviolet absorption satisfy the above-described values. .

In the present invention, it is also a preferred embodiment that a light stabilizer is dispersed in the light-resistant layer 1. The light stabilizers here are roughly divided into two types, quenchers and HALS, and quenchers generally have a function of de-exciting active molecules (eg singlet oxygen ¹ O ₂ etc.) in an excited state. Have HALS is thought to function as a radical scavenger generated by ultraviolet rays, although the mechanism is still unclear. By dispersing these in the light-resistant layer 1, the photocatalytic reaction of the metal oxide particles having ultraviolet absorbing ability can be suppressed.
Examples of the quencher include metal complexes such as dithiol-based nickel complexes and dithiol-based copper complexes. HALS is a hindered amine compound, which is a compound in which all hydrogens on carbons at the 2nd and 6th positions of the piperidine ring are substituted with methyl groups, for example, bis- [2,2,6,6 -Tetramethyl-4-piperidinyl] sebacic acid, bis- [N-methyl-2,2,6,6-tetramethyl-4-piperidinyl] sebacic acid, tetrakis (2,2,6,6-tetramethyl-4 -Piperidinyl) -1,2,3,4-butanetetracarboxylic acid, tridecyl-1,2,3,4-butanetetracarboxylic acid, succinic acid-bis (2,2,6,6-tetramethyl-4- Piperidyl) ester, dimethyl succinate 1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine, and the like, and mixtures thereof. In the present invention, it is particularly preferable to use HALS.

  When the light stabilizer is a hindered amine compound, the amount of the light stabilizer is 0.1 to 30 parts by weight with respect to 100 parts by weight of the metal oxide particles contained in the resin binder of the light-resistant layer 1. It is preferable to add at 0.5 to 20 parts by weight. Further, when the light stabilizer is a quencher, it is preferably added in a proportion of 0.01 to 20 parts by weight, more preferably 100 parts by weight of the metal oxide particles contained in the resin binder of the light-resistant layer 1. Is 0.1 to 15 parts by weight. When the blending amount of the light stabilizer is in the above range, the catalytic activity reaction of the metal oxide particles is suppressed, and the long-term weather resistance is further improved. When the blending amount of the light stabilizer is small, the catalyst activity suppressing effect may be reduced. Conversely, when the upper limit is exceeded, a problem that undissolved substances aggregate in the resin binder may occur.

In the present invention, examples of the resin constituting the base resin film include polyolefin resins such as polyethylene, polypropylene, polystyrene, and polymethylpentene, alicyclic polyolefin resins, polyamide resins such as nylon 6 and nylon 66, aramid resins, Polyester resin such as polyethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate, polybutyl succinate, polyethylene-2,6-naphthalate, polycarbonate resin, polyarylate resin, polyacetal resin, polyphenylene sulfide resin, tetrafluoroethylene resin, trifluoride Fluorine resin such as ethylene resin, trifluorochloroethylene resin, tetrafluoroethylene-6-propylene copolymer, vinylidene fluoride resin, acrylic resin Methacrylic resins, can be used polyacetal resins, polyglycolic acid resins, and polylactic acid resins, and the like. Among these resins, polyester is particularly preferably used from the viewpoint of strength, heat resistance, and transparency.
These resins may be homo-resins, copolymerized or blends of two or more. In the resin, various additives such as antioxidants, antistatic agents, crystal nucleating agents, inorganic particles, organic particles, thickeners, heat stabilizers, lubricants, infrared rays, etc. are added to the extent that the characteristics of the invention are not impaired. An absorber, an ultraviolet absorber, a dopant for adjusting the refractive index, and the like may be added.

  In the present invention, a laminated film can be used as the base resin film. As the resin constituting the laminated film used in the present invention, polyester is preferably used. The polyester referred to in the present invention refers to a homopolyester or a copolyester that is a polycondensate of a dicarboxylic acid skeleton component and a diol skeleton component. Here, typical examples of the homopolyester include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, poly-1,4-cyclohexanedimethylene terephthalate, and polyethylene diphenylate. is there. In particular, since polyethylene terephthalate is inexpensive, it can be used for a wide variety of applications.

In addition, the copolymer polyester in the present invention includes a dicarboxylic acid component skeleton and a diol component skeleton as essential components, and a copolymer having at least three or more components selected from the dicarboxylic acid component skeleton and the diol component skeleton described below. Defined as a condensate.
Examples of the dicarboxylic acid skeleton component include terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 4,4′-diphenyldicarboxylic acid. 4,4′-diphenylsulfone dicarboxylic acid, adipic acid, sebacic acid, dimer acid, cyclohexanedicarboxylic acid and ester derivatives thereof. Examples of the glycol skeleton component include ethylene glycol, 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentadiol, diethylene glycol, polyalkylene glycol, and 2,2-bis (4 '-Β-hydroxyethoxyphenyl) propane, isosorbate, 1,4-cyclohexanedimethanol and the like. The polyester can contain a skeleton derived from other components as long as the effects of the present invention are not impaired.

The base resin film used in the present invention has a structure in which a layer made of resin A (A layer) and a layer made of resin B (B layer) are alternately laminated by combining A layer and B layer by 10 layers or more. It is preferable that it is a laminated film.
Here, alternately laminating a layer made of resin A (A layer) and a layer made of resin B (B layer) is a portion having a structure in which A layer and B layer are regularly laminated in the thickness direction. Is defined to exist. That is, it is preferable that the arrangement order in the thickness direction of the A layer and the B layer in the base resin film used in the present invention is not in a random state, and the third layer or more other than the A layer and the B layer is the The order of arrangement is not particularly limited. In addition to the A layer and the B layer, when having a C layer made of the resin C, the layers are laminated in a regular permutation such as A (BCA) n, A (BCBA) n, and (BABCBA) n. Is a more preferred embodiment. Here, n is the number of repeating units. For example, when n = 3 in A (BCA) n, it represents that stacked in a permutation of ABCABCABCA in the thickness direction.
By setting it as such a laminated structure, the multi-interface reflection interferes and the resin film which has a specific high reflection zone can be obtained. Henceforth, a reflection zone shall show the wavelength zone | band whose reflectance represented by the measuring method mentioned later is 30% or more. When several reflection bands are observed, it is defined as being on the highest wavelength side. In order to obtain a desired reflection band, it is preferable to have a relational expression satisfying the following formula 1. The reflection wavelength obtained by Equation 1 is called primary reflection, and there may be cases where higher-order reflections such as second-order, third-order, and fourth-order appear based on the first-order reflection.
2 × (na · da + nb · db) = λ Equation 1
na: In-plane average refractive index of the A layer nb: In-plane average refractive index of the B layer da: Layer thickness (nm) of the A layer
db: Layer thickness of layer B (nm)
λ: main reflection wavelength (primary reflection wavelength)
The shape of this reflection band can be selected by the manner of arrangement with respect to the thickness direction of the layer thickness. For example, when the thickness of the layer is constant from one surface to the opposite surface, reflected light having a narrow bandwidth and high intensity can be obtained. In addition, as the thickness of the layer changes from one surface to the opposite surface side in a linear function, broadband reflected light with a wide bandwidth can be obtained.
The number of stacked layers is preferably at least 10 layers including the A layer and the B layer. When the number of stacked layers decreases, a sufficient reflectance cannot be obtained. The number of stacked layers is more preferably 50 layers or more, and still more preferably 200 layers or more. The upper limit is not particularly limited, but it is preferably 3000 layers or less from the viewpoint of increasing the size of the laminating apparatus, increasing the film thickness, or increasing the cost.

  In the base material resin film having a laminated structure used in the present invention, it is preferable that the ratio Z of the thicknesses of the adjacent A layer and B layer is 0.8 or more and 5 or less. Here, the layer corresponding to the outermost layer of the base resin film is defined as A layer. Further, the ratio Z of the thicknesses of the A layer and the B layer is obtained by averaging the ratios of the thicknesses of the A layer and the B layer in the intermediate portion when the film cross section is divided into three in the thickness direction. In addition, even a layer in the middle part is excluded when the dividing line straddles it. The thickness ratio Z is more preferably 0.9 or more and 1.1 or less. When the thickness ratio Z is smaller than 0.8 or larger than 5, the reflectance decreases and the distribution of the reflectance in the reflection band tends to increase. Further, when the thickness ratio Z is 0.9 or more and 1.1 or less, the reflectance distribution in the reflection band becomes small and high-order reflection hardly occurs, which is a more preferable embodiment.

  Moreover, it is preferable that the variation in the ratio of the thicknesses of the adjacent A layer and B layer is ± 20% or less. This variation is obtained by dividing the difference between the maximum thickness ratio and the minimum thickness ratio by the central thickness ratio with respect to the distribution of the thickness ratio between the A layer and the B layer that contributes to the reflection performance. If the variation is larger than ± 20%, it becomes difficult to obtain a sufficient reflectance, and reflection may appear in addition to the designed reflection peak, resulting in noise as a filter.

  The thickness of the laminated film is preferably 5 μm or more in order to exhibit a certain level of strength as a support. On the other hand, the upper limit value of the thickness is not particularly limited, but is preferably less than 500 μm from the viewpoint of film forming properties. Moreover, it is preferable that the thickness of A layer and B layer exists in the range of 20 nm-500 nm.

The base resin film used in the present invention is preferably a laminated film having a structure in which layers made of a crystalline resin and layers made of an amorphous resin are alternately laminated. In the present invention, an amorphous resin means a temperature of 10 ° C./min. It is defined as a resin having a crystallization exothermic peak with an amount of heat of 3 J / g or less when the temperature is lowered at a rate of. A case where the heat amount of the crystallization exothermic peak is larger than 3 J / g is defined as a crystalline resin.
Examples of the crystalline resin here include polyester, polyamide, and polypropylene, and a more preferable example of the crystalline resin is polyester. Further, examples of the amorphous resin include polycarbonate, polystyrene, polyvinyl chloride, and the like, and a resin whose crystallinity is lowered by introducing a heterogeneous structure also corresponds to this. A particularly preferred example is a polyester in which a dicarboxylic acid component and a diol component are partially copolymerized by 15 to 60%. In the present invention, as an example of the most preferable combination of a crystalline resin and an amorphous resin, the crystalline resin is polyethylene terephthalate, and the amorphous resin is an ethylene terephthalate polycondensate copolymerized with 20 to 40 mol% of cyclohexanedimethanol. There are cases. In this case, the same basic skeleton is ethylene terephthalate, and an ethylene terephthalate polycondensate obtained by copolymerizing 20 to 40 mol% of cyclohexanedimethanol corresponds to an amorphous resin. By alternately laminating a layer made of a crystalline resin and a layer made of an amorphous resin in this way, the difference in refractive index increases due to stretching and heat treatment, the reflection characteristics are dramatically improved, and reflection by heating This is because the change in characteristics becomes small. The difference in preferred in-plane average refractive index between the layer made of crystalline resin and the layer made of amorphous resin is 0.03 or more, more preferably 0.05 or more, and still more preferably 0.1 or more. .

  The configuration of the laminated film is a preferred embodiment in which the crystalline resin is the A layer described above and the amorphous resin is the B layer. By adopting such a configuration, it is possible to form a film without causing problems such as adhesion and uneven stretching in the stretching and heat treatment steps.

  When the amorphous resin is a copolyester, the weather resistance is greatly reduced, but by adopting a structure that imparts the weather resistance of the present invention, it exhibits excellent weather resistance and the reflection characteristics over time. There is almost no decline.

  Further, the weather resistant resin film of the present invention preferably has a haze of 5% or less. The haze is more preferably 4.5% or less. When the haze is larger than 5%, the visibility tends to decrease.

  The weather resistant resin film of the present invention preferably has a reflectance of 30% or more with respect to light in any part of a wavelength range of 250 to 2500 nm. The shape of the band is not particularly limited as long as it is narrow band or wide band, and is not particularly limited as long as the number of bands is one or more. Further, the reflectivity is measured using an integrating sphere with a spectrophotometer for light incident from a direction whose difference angle from the vertical axis is 10 ° with respect to the film surface unless otherwise specified. Says the reflectance. A more preferable reflectance is preferably 60% or more, and more preferably 80% or more. When the reflectance is 60% or more, extremely high reflection performance can be obtained, which makes it suitable as a filter, a reflection plate, and a decorative material. The incident angle referred to here is the difference angle between the direction perpendicular to the film surface and the direction in which light enters.

  The weather resistant resin film of the present invention preferably has a reflectance of at least 40% in a band having a wavelength of 420 to 780 nm. When the reflectance of the wavelength band of 420 to 780 nm is 40% or more, visible light is selectively reflected, and it is suitable as a plated decorative material or a reflector for a concentrating solar cell. A more preferable reflectance is preferably 60% or more, and more preferably 80% or more. When the reflectance is 60% or more, extremely high designability can be obtained, and high light collection efficiency can be obtained.

  The weather resistant resin film of the present invention is suitably used as a design film. The film for design is a film for imparting a color or a specific color pattern, for example, a decorative film for a design used for an automobile interior or exterior, a decoration for a design used for various packaging Film, anti-counterfeiting film for the purpose of authenticity determination used for banknotes, cash vouchers, gift certificates, securities, etc., and a hologram substrate film or a reflector film.

Moreover, the weather-resistant resin film of this invention, especially the thing of a base film resin film is a laminated film is suitable as a reflector for solar cells. Furthermore, a weather-resistant resin film having a reflectance of 80% or more in any part of the wavelength range of 300 to 2500 nm is more suitable as a solar cell reflector. More preferably, a weather-resistant resin film having a reflectance of 90% or more in any part of a wavelength band of 300 to 2500 nm is more suitable as a solar cell reflector. Most preferably, a weather-resistant resin film having a reflectance of at least a wavelength of 450 nm to 1100 nm of 80% or more is more suitable as a solar cell reflector.
Solar cells include silicon type (single crystal, polycrystal and amorphous), compound type and dye sensitized type solar cells, but silicon type solar cells are often used in terms of power generation cost. In these solar cells, a solar cell reflector called a back sheet is used. Although this solar cell reflector improves the power generation efficiency by reflecting sunlight that has passed through the cell or not through the cell, conventionally, a white sheet in which a pigment is dispersed has been often used. By using the weather resistant resin film of the present invention, a higher reflectivity can be obtained, so that the power generation efficiency is improved and the reflectivity is not lowered by heating during actual use, so that the high efficiency is maintained over a long period of time. It will be possible.
In addition, the present inventors can obtain higher power generation efficiency and can perform photoelectric conversion in a solar battery cell when the reflectance of at least one of the bands of wavelengths of 300 to 2500 nm is 80% or more. The present inventors have found that the power generation efficiency can be further improved by the effect of preventing the temperature rise of the solar battery cell because only a short wavelength can be efficiently reflected. Therefore, the power generation efficiency becomes higher as the reflectance becomes 90% and the reflectance becomes 95% or more. In addition, when the reflectance at a wavelength of 450 nm to 1100 nm is at least 80%, particularly in a silicon solar cell, higher power generation efficiency is obtained.
Moreover, it is suitable also as a mirror and filter for concentrating solar cells that the reflectance of the band of any one of wavelength 300-2500nm is 80% or more. Here, the concentrating solar cell is a system that condenses sunlight using a mirror or lens on a solar cell to generate power. By using the weather-resistant resin film of the present invention in an apparatus for condensing light, it is possible to extract only the wavelength of sunlight that can be photoelectrically converted for the solar battery cell, so that the temperature of the cell can be prevented and the present invention can be prevented. In order to prevent changes in optical properties due to heating and light deterioration over time, which is a feature of the product, there is almost no change in performance even in harsh outdoor environments, so the reduction in power generation efficiency over time can be made extremely small. .
When the cell is a silicon-type concentrating solar cell and the concentrating device is a mirror type, the weather-resistant resin film of the present invention has a reflectance of at least 90% in the wavelength range of 450 to 1050 nm and a wavelength of 1200 to 1200. The reflectance at 2000 nm is preferably 30% or less. When this weather resistant resin film is used as a mirror, high power generation efficiency can be obtained.
When the cell is a silicon-type concentrating solar cell and the concentrating device is a lens type, the weather-resistant resin film of the present invention has a reflectance of 20% or less in a wavelength range of at least 450 to 1050 nm. The reflectance at 1100 to 2000 nm is preferably 90% or more. When this weather resistant resin film is installed as a filter before and after the lens, high power generation efficiency can be obtained.

  In addition, the weather-resistant resin film of the present invention has an easy-adhesion layer, an easy-slip layer, a hard coat layer, an antistatic layer, an anti-abrasion layer, an anti-reflection layer, a color correction layer, an electromagnetic wave on the surface separately from the light-resistant layer. Functional layers such as a shield layer, a printed layer, a metal layer, a transparent conductive layer, a gas barrier layer, a hologram layer, a release layer, an adhesive layer, and an adhesive layer may be formed.

  In particular, when the weatherable resin film of the present invention is used for a design film, a color absorbing layer that absorbs black or a color complementary to a reflection band, a metal layer such as aluminum, silver, gold, and indium, or a printing layer It is preferable to form on the adhesive layer and the film surface.

  Next, the preferable manufacturing method of the weather resistant resin film of this invention is demonstrated below.

If necessary, the thermoplastic resin pellets are pre-dried in hot air or under vacuum and supplied to an extruder. In the extruder, the resin heated and melted to a temperature equal to or higher than the melting point is homogenized by a gear pump or the like, and foreign matter or denatured resin is removed through a filter or the like. In addition, when taking a film form in which 10 layers or more of layers made of resin A and B are arranged alternately, two types of thermoplastic resins are similarly heated and melted in two extruders. , Feed into the laminating device. As a laminating apparatus, a method of laminating in multiple layers using a multi-manifold die, a field block, a static mixer, etc. can be used, but here, a feed block that can individually control the layer thickness of each layer has a laminating accuracy. high.
Further, in order to accurately control the thickness of each layer, it is preferable to use a feed block provided with fine slits for adjusting the flow rate of each layer in electric discharge machining or wire electric discharge machining with a machining accuracy of 0.1 mm or less. Moreover, in order to suppress the wall resistance in the feed block, the roughness of the wall surface is preferably 0.4 S or less, or the contact angle with water at room temperature is 30 ° or more.

  Moreover, about the layer thickness of each layer, since the desired reflection zone is obtained based on the above-described formula 1, the thickness of each layer is adjusted by adjusting the discharge of each extruder according to the refractive index of the resin used. can do. As for the number of layers, it is preferable that the number of layers is 10 or more in order to at least make the reflectance of the reflection band 30% or more. In particular, when a high reflectance is required, such as a decorative film or a solar cell reflector, the number of laminated layers is preferably 100 or more.

  The single film or the laminated film thus obtained is extruded onto a cooling body such as a casting drum, and cooled and solidified to obtain a casting film. At this time, using a wire-like, tape-like, needle-like, or knife-like electrode, it is brought into close contact with a cooling body such as a casting drum by electrostatic force and rapidly cooled and solidified, or from a slit-like, spot-like or planar device A method in which air is blown out and brought into close contact with a cooling body such as a casting drum and rapidly solidified, and a method in which the air is brought into close contact with the cooling body with a nip roll and rapidly solidified is preferably used.

  The casting film thus obtained is preferably biaxially stretched as necessary. Biaxial stretching refers to stretching in the longitudinal direction and the width direction. Stretching may be performed sequentially biaxially or simultaneously in two directions. Further, the film may be redrawn in the longitudinal and / or width direction. In particular, in the present invention, it is preferable to use simultaneous biaxial stretching from the viewpoint of suppressing in-plane orientation difference and suppressing surface scratches.

  First, the case of sequential biaxial stretching will be described. Here, stretching in the longitudinal direction refers to stretching for imparting molecular orientation in the longitudinal direction to the film, and is usually performed by a difference in peripheral speed of the roll, and this stretching may be performed in one step. Alternatively, a plurality of roll pairs may be used in multiple stages. Although the stretching ratio varies depending on the type of resin, it is usually preferably 2 to 15 times. When polyethylene terephthalate is used for any of the resins constituting the laminated film, a magnification of 2 to 7 times is particularly preferably used. It is done. The stretching temperature is preferably in the range of the glass transition temperature of the resin constituting the laminated film to the glass transition temperature + 100 ° C.

  The uniaxially stretched film thus obtained is subjected to surface treatment such as corona treatment, flame treatment and plasma treatment as necessary, and then functions such as slipperiness, easy adhesion and antistatic properties are provided. It may be applied by in-line coating.

  The stretching in the width direction refers to stretching for giving the film an orientation in the width direction. Usually, the tenter is used to convey the film while holding both ends of the film with clips, and the film is stretched in the width direction. Although the stretching ratio varies depending on the type of resin, it is usually preferably 2 to 15 times. When polyethylene terephthalate is used for any of the resins constituting the laminated film, a magnification of 2 to 7 times is particularly preferably used. It is done. The stretching temperature is preferably in the range of the glass transition temperature of the resin constituting the laminated film to the glass transition temperature + 120 ° C.

  The film biaxially stretched in this manner is preferably subjected to a heat treatment not less than the stretching temperature and not more than the melting point in the tenter in order to impart flatness and dimensional stability. After being heat-treated in this way, it is gradually cooled down uniformly, then cooled to room temperature and wound up. Moreover, you may use a relaxation process etc. together in the case of annealing from heat processing as needed.

  Next, the case of simultaneous biaxial stretching will be described next. In the case of simultaneous biaxial stretching, the resulting cast film is subjected to surface treatment such as corona treatment, flame treatment, and plasma treatment as necessary, and then, such as slipperiness, easy adhesion and antistatic properties. The function may be imparted by in-line coating.

  Next, the cast film is guided to a simultaneous biaxial tenter, and conveyed while holding both ends of the film with clips, and stretched in the longitudinal direction and the width direction simultaneously and / or stepwise. Simultaneous biaxial stretching machines include pantograph, screw, drive motor, and linear motor stretching machines, but the stretching ratio can be changed arbitrarily, and the drive can be relaxed at any location. A motor type or linear motor type stretching machine is preferred. Although the draw ratio varies depending on the type of resin, it is usually preferably 6 to 50 times as the area magnification. When polyethylene terephthalate is used as one of the resins constituting the laminated film, the area magnification is 8 to A magnification of 30 times is particularly preferably used. In particular, in the case of simultaneous biaxial stretching, in order to suppress the in-plane orientation difference, it is preferable that the stretching ratios in the longitudinal direction and the width direction are the same, and the stretching speeds are also substantially equal. The stretching temperature is preferably in the range of the glass transition temperature of the resin constituting the laminated film to the glass transition temperature + 120 ° C.

  In order to impart flatness and dimensional stability, the film biaxially stretched in this manner is preferably subsequently subjected to a heat treatment not less than the stretching temperature and not more than the melting point in the tenter. In order to suppress the distribution of the main alignment axis in the width direction during this heat treatment, it is preferable to perform a relaxation treatment in the longitudinal direction immediately before and / or immediately after entering the heat treatment zone. The biaxially stretched film is heat-treated in this way, and then uniformly cooled, cooled to room temperature and wound up. Moreover, you may perform a relaxation | loosening process in a longitudinal direction and / or the width direction at the time of annealing from heat processing as needed. When the relaxation treatment is instantaneously performed in the longitudinal direction immediately before and / or immediately after entering the heat treatment zone, the difference in reflectance in the film width direction can be made ± 10% or less.

  A light-resistant layer in which metal oxide particles are dispersed is provided on the surface of the biaxially stretched film thus obtained. Coating is performed using a coating technique such as a gravure coater, a metering bar, or roll coating, and then a coating film is formed by heat drying, UV crosslinking, or electron beam crosslinking. Furthermore, as a prescription for preventing the ultraviolet light deterioration of the light-resistant layer 1, it is necessary to provide the light-resistant layer 2 in which an organic ultraviolet absorber is further dispersed on the light-resistant layer 1. In addition, if a hindered amine compound is dispersed in the light-resistant layer 1, a better effect can be obtained. At this time, in order to improve the adhesion between the base resin film and the light-resistant layer, corona treatment, frame treatment, alkali treatment, or the like can be performed. Or you may provide an easily bonding layer in a base resin film. Moreover, you may provide an adhesive layer and a hard-coat layer in a base resin film according to a use.

  The weather resistant resin film of the present invention thus obtained is excellent in transparency and long-term weather resistance, and therefore can be suitably used as an industrial material or an optical material for outdoor use. In particular, by applying the weather resistant resin film of the present invention to an optical interference reflection film having an alternately laminated structure, the weather resistance life can be greatly improved.

The evaluation method of physical properties used in the present invention is as follows.
(Method for evaluating physical properties)
(1) Lamination Thickness, Number of Laminations The layer structure of the base resin film was determined by observing an electron microscope for a sample cut out of a cross section using a microtome. That is, using a transmission electron microscope HU-12 (manufactured by Hitachi, Ltd.), the cross section of the film was magnified 40000 times, a cross-sectional photograph was taken, and the layer structure and each layer thickness were measured. The embodiment of the present invention was not carried out because sufficient contrast was obtained. However, depending on the combination of thermoplastic resins used, the contrast may be increased by using a dyeing technique using RuO ₄ or OsO ₄ .

(2) Reflectance A spectrophotometer (U-3410 Spectrophotometer) manufactured by Hitachi, Ltd. was fitted with a φ60 integrating sphere 130-0632 (Hitachi Ltd.) and a 10 ° inclined spacer, and the reflectance was measured. The band parameter was set to 2 / servo, the gain was set to 3, and the range from 187 nm to 2600 nm was set to 120 nm / min. Measured at a detection speed of. In order to standardize the reflectance, an attached Ba ₂ SO ₄ plate was used as a standard reflecting plate. When the wavelength band having a reflectance of 30% or less was 100 nm or less, the reflection wavelength was determined as the peak top wavelength. Further, when the wavelength band having a reflectance of 30% or more has a range of 100 nm or more, the wavelength of the reflection band is represented by a region where the reflectance is 30% or more. The reflectance was obtained by averaging the reflectance in the band from the high wavelength end of −30 nm at which the reflectance is 30% or higher to the low wavelength end of +30 nm at which the reflectance is 30% or higher.

(3) Intrinsic viscosity Calculated from the solution viscosity measured at 25 ° C in orthochlorophenol. The solution viscosity was measured using an Ostwald viscometer. The unit is [dl / g]. The n number was 3, and the average value was adopted.

(4) Haze It measured using the direct reading type haze meter HGM-2DP (for C light sources) (Suga Test Instruments Ltd.). The haze (%) was calculated by dividing the diffuse transmittance by the total light transmittance and multiplying by 100. The number of n was 5 and the average value was adopted.

(5) Elongation at break Using a tensile tester “Tensilon” (registered trademark) (AMF / RTA-100 manufactured by Orientec Co., Ltd.), a sample film having a width of 10 mm is set so that the length between chucks is 100 mm. A tensile test was performed at a tensile speed of 300 mm / min under the conditions of ° C and 65% RH, and the breaking elongation at this time was determined. Here, these values are average values when measured 10 times.

(6) Elongation retention rate Using an accelerated weathering tester “I Super” (registered trademark) (UV tester specification) SUV-W131 (Iwasaki Electric Co., Ltd.), the resin film was irradiated with ultraviolet rays and condensed at 10 cycles. 20 cycles were performed. The conditions at this time are as follows.
Light source lamp: Metal halide lamp UV wavelength: 295-450 nm
UV illumination: 100 mW / cm2 ± 5%
1 cycle: irradiation time 8 hours (temperature 60 ° C., humidity 50% RH)
Condensation time 4 hours (temperature 35 ° C, humidity 90% RH)
From the breaking elongation before and after the weather test, the elongation retention was calculated by the following formula. ◎ when the elongation retention is 90% or more, ◯ when it is 70% or more and less than 90%, ● when it is 50% or more and less than 70%, △ when it is 30% or more and less than 50%, Those less than 30% were evaluated as x.
Elongation retention (%) = (breaking elongation after weathering test / breaking elongation before weathering test) × 100
(7) Average particle diameter The average particle diameter of the metal oxide particles dispersed in the binder was measured using a light scattering photometer DLS-6000 (Otsuka Electronics Co., Ltd.).

Example 1
As a thermoplastic resin, polyethylene terephthalate (PET) having an intrinsic viscosity of 0.65 is melted at a temperature of 280 ° C. with an extruder, passed through a gear pump and a filter, supplied to a die, and molded into a sheet, It was rapidly cooled and solidified on a casting drum maintained at a surface temperature of 25 ° C. by electrostatic application (DC voltage 8 kV). The obtained cast film was heated with a group of rolls set at a temperature of 90 ° C. and stretched 3.3 times in the longitudinal direction. Then, it was led to a tenter, preheated with hot air at a temperature of 120 ° C., and then stretched 3.5 times in the transverse direction. The stretched film was directly heat-treated in a tenter with hot air at a temperature of 230 ° C., then subjected to a relaxation treatment of 5% in the width direction at the same temperature, gradually cooled to room temperature, and wound up. The thickness of the biaxially stretched film thus obtained was 38 μm.

  The biaxially stretched film thus obtained was subjected to surface corona discharge treatment and then 24 parts of zinc oxide particles having an average particle diameter of 0.05 μm whose surface was treated with zirconia, acrylic resin (“Acridic” (registered) Trademark) A-195: Dainippon Ink Chemical Co., Ltd.) 24 parts, thermal crosslinking agent ("Sumijoule" (registered trademark) N3200: Bayer Co., Ltd.) 2 parts, and a solution consisting of 52 parts of methyl ethyl ketone in a bar coater Then, coating and heat drying were performed to form a light-resistant layer 1 having a coating thickness of 10 μm. Further on this, 42 parts of a benzotriazole-based ultraviolet absorber (“Udouble” (registered trademark) UV-G13: manufactured by Nippon Shokubai Co., Ltd.), a thermal crosslinking agent (“Sumidur” (registered trademark) N3200: manufactured by Bayer) 2 And a solution comprising 56 parts of toluene were applied and heat-dried. The coating thickness at this time is 1 μm. The obtained results are shown in Table 1.

(Example 2)
A biaxially stretched film obtained under the same conditions as in Example 1 was subjected to surface corona discharge treatment, and then 24 parts of zinc oxide particles having a particle diameter of 0.035 μm whose surface was treated with zirconia were treated with acrylic resin (“Aclidick”). "(Registered trademark) A-195: manufactured by Dainippon Ink & Chemicals, Inc.) 24 parts, thermal crosslinking agent (" Sumidur "(registered trademark) N3200: manufactured by Bayer) 2 parts, and a solution consisting of 52 parts of methyl ethyl ketone, Coating and heat drying were performed with a bar coater to form a light-resistant layer 1 having a coating thickness of 10 μm. Further thereon, 42 parts of a benzotriazole ultraviolet absorber (Udable UV-G13: manufactured by Nippon Shokubai Co., Ltd.), 2 parts of a thermal crosslinking agent (“Sumijoule” (registered trademark) N3200: manufactured by Bayer), and 56 parts of toluene The solution consisting of was applied and heat-dried. The coating thickness at this time is 1 μm. The obtained results are shown in Table 1.

(Example 3)
The biaxially stretched film obtained under the same conditions as in Example 1 was subjected to surface corona discharge treatment, and then the surface was treated with zirconia-treated zinc oxide particles having a particle diameter of 0.05 μm, 24 parts, acrylic resin 24 parts, 1.5 parts of molecular weight type HALS (“Adeka Stub” (registered trademark) LA-68LD: manufactured by Asahi Denka Kogyo Co., Ltd.), 1 part of thermal crosslinking agent (“Sumijour” (registered trademark) N3200: manufactured by Bayer), and A solution comprising 52 parts of methyl ethyl ketone was applied and heat-dried with a bar coater to form a light-resistant layer 1 having a coating thickness of 10 μm. Further thereon, 42 parts of a benzotriazole-based ultraviolet absorber (“Udable” (registered trademark) UV-G13: manufactured by Nippon Shokubai Co., Ltd.), a thermal crosslinking agent (“Sumijoule” (registered trademark) N3200 (manufactured by Bayer)) 2 And a solution consisting of 56 parts of toluene were coated and heat-dried, and the coating thickness at this time was 1 μm.

Example 4
A biaxially stretched film obtained under the same conditions as in Example 1 was subjected to surface corona discharge treatment, and then 24 parts of zinc oxide particles having a particle diameter of 0.08 μm whose surface was treated with zirconia was treated with acrylic resin (“Acridic "(Registered trademark) A-195: manufactured by Dainippon Ink & Chemicals, Inc.) 24 parts, thermal crosslinking agent (" Sumidur "(registered trademark) N3200: manufactured by Bayer) 2 parts, and a solution consisting of 52 parts of methyl ethyl ketone, Coating and heat drying were performed with a bar coater to form a light-resistant layer 1 having a coating thickness of 10 μm. Further on this, 42 parts of a benzotriazole-based ultraviolet absorber (“Udable” (registered trademark) UV-G13: manufactured by Nippon Shokubai Co., Ltd.), a thermal crosslinking agent (“Sumijoule” (registered trademark) N3200: manufactured by Bayer) 2 And a solution comprising 56 parts of toluene were applied and heat-dried. The coating thickness at this time is 1 μm. The obtained results are shown in Table 1.

(Example 5)
A biaxially stretched film obtained under the same conditions as in Example 1 was subjected to surface corona discharge treatment, and then 24 parts of titanium oxide particles having a particle diameter of 0.05 μm whose surface was treated with zirconia, acrylic resin (“Acridic” "(Registered trademark) A-195: manufactured by Dainippon Ink & Chemicals, Inc.) 24 parts, thermal crosslinking agent (" Sumidur "(registered trademark) N3200: manufactured by Bayer) 2 parts, and a solution consisting of 52 parts of methyl ethyl ketone, Coating and heat drying were performed with a bar coater to form a light-resistant layer 1 having a coating thickness of 10 μm. Further on this, 42 parts of a benzotriazole-based ultraviolet absorber (“Udable” (registered trademark) UV-G13: manufactured by Nippon Shokubai Co., Ltd.), a thermal crosslinking agent (“Sumijoule” (registered trademark) N3200: manufactured by Bayer) 2 And a solution comprising 56 parts of toluene were applied and heat-dried. The coating thickness at this time is 1 μm. The obtained results are shown in Table 1.

(Example 6)
The biaxially stretched film obtained under the same conditions as in Example 1 was subjected to surface corona discharge treatment, and then 24 parts of zinc oxide particles having a particle diameter of 0.05 μm whose surface was treated with zirconia, acrylic resin (“Acridic” "(Registered trademark) A-195: manufactured by Dainippon Ink & Chemicals, Inc.) 24 parts, thermal crosslinking agent (" Sumidur "(registered trademark) N3200: manufactured by Bayer) 2 parts, and a solution consisting of 52 parts of methyl ethyl ketone, Coating and heat drying were performed with a bar coater to form a light-resistant layer 1 having a coating thickness of 10 μm. Further, 42 parts of a benzophenone ultraviolet absorber (UVA-935LH: manufactured by BASF Japan), 2 parts of a thermal crosslinking agent (“Basonate” (registered trademark) HI100: manufactured by BASF Japan), and 56 parts of toluene are included. The solution was applied and heat-dried. The coating thickness at this time is 1.5 μm. The obtained results are shown in Table 1.

(Example 7)
As the thermoplastic resin A, polyethylene terephthalate (PET) [F20S manufactured by Toray Industries, Inc.] having an intrinsic viscosity of 0.65 was used. Further, as the thermoplastic resin B, polyethylene terephthalate (CHDM copolymerized PET) obtained by copolymerizing 30 mol% of cyclohexanedimethanol with respect to ethylene glycol [PETG6763 manufactured by Eastman] was used. These thermoplastic resin A and thermoplastic resin B were each dried and then supplied to an extruder. The thermoplastic resin A and the thermoplastic resin B were each melted at a temperature of 280 ° C. with an extruder, passed through a gear pump and a filter, and then merged in a 201-layer feed block. The joined thermoplastic resins A and B are formed so that the thickness of each layer is almost constant from the surface side to the opposite surface side in the feed block, the thermoplastic resin A is 101 layers, and the thermoplastic resin B is 100 layers. It was set as the structure laminated | stacked alternately in the thickness direction. The thickness of each layer was adjusted by the shape of fine slits (formed with a processing accuracy of 0.01 mm) provided in the flow path of each layer in the feed block. In addition, both surface layer parts were made to become the thermoplastic resin A. Here, the shape of the feed block and the discharge amount were adjusted so that the thickness ratio of the adjacent A layer and B layer (A layer thickness / B layer thickness) was 2.0. A casting drum in which a total of 201 layers thus obtained was supplied to a fishtail die, formed into a sheet shape, and then maintained at a surface temperature of 25 ° C. by electrostatic application (DC voltage 8 kV). It was rapidly cooled and solidified above. The obtained cast film was heated by a group of rolls set to a temperature of 90 ° C. and stretched 3.4 times in the longitudinal direction. Then, it was led to a tenter, preheated with hot air at a temperature of 120 ° C., and then stretched 4.2 times in the transverse direction. The stretched film was directly heat-treated in a tenter with hot air at a temperature of 230 ° C., then subjected to a relaxation treatment of 5% in the width direction at the same temperature, gradually cooled to room temperature, and wound up. The biaxially stretched film thus obtained had a thickness of 18 μm. Regarding the layer thickness of each layer, the layer thickness of the A layer was 116 nm, and the layer thickness of the B layer was 58 nm.

  The light-resistant layer 1 and the light-resistant layer 2 were provided on the surface of the film thus obtained under the same conditions as in Example 1. The obtained results are shown in Table 1.

(Example 8)
A light-resistant layer 1 and a light-resistant layer 2 were provided on the surface of a biaxially stretched film obtained under the same film forming conditions as in Example 7 under the same conditions as in Example 3. The obtained results are shown in Table 1.

Example 9
As the thermoplastic resin A, polyethylene terephthalate (PET) [F20S manufactured by Toray Industries, Inc.] having an intrinsic viscosity of 0.65 was used. Further, as the thermoplastic resin B, polyethylene terephthalate (CHDM copolymerized PET) obtained by copolymerizing 30 mol% of cyclohexanedimethanol with respect to ethylene glycol [PETG6763 manufactured by Eastman] was used. These thermoplastic resin A and thermoplastic resin B were dried and then supplied to an extruder. The thermoplastic resin A and the thermoplastic resin B were each brought into a molten state at a temperature of 280 ° C. by an extruder, passed through a gear pump and a filter, and then joined by a feed block of 801 layers. This feed block is a composite of three slit members having 267 slits, and the joined thermoplastic resin A and thermoplastic resin B are separated from the surface side in the thickness of each layer in the feed block. The thickness was gradually increased toward the side (slope type), and a structure in which 401 layers of thermoplastic resin A and 400 layers of thermoplastic resin B were alternately laminated in the thickness direction was obtained. The slit shape was 40 mm in length and (slit area on the side where no resin was introduced) / (slit area on the side where resin was introduced) was 0.5. The thickness of each layer was adjusted by the shape of fine slits (formed with a processing accuracy of 0.01 mm) provided in the flow path of each layer in the feed block. In addition, both surface layer parts were made to become the thermoplastic resin A. Here, the shape of the feed block and the discharge amount were adjusted so that the thickness ratio of the adjacent A layer and B layer was 0.95. After the laminated body composed of the total of 801 layers thus obtained is supplied to the multi-manifold die, and further, a layer made of the thermoplastic resin A supplied from another extruder is formed on the surface layer, and then formed into a sheet shape Then, it was rapidly cooled and solidified on a casting drum whose surface temperature was kept at 25 ° C. by electrostatic application.

The film forming conditions and coating conditions were the same as in Example 5 except that the film thickness was 130 μm.
The obtained results are shown in Table 1.

(Comparative Example 1)
It implemented on the conditions similar to Example 1 except not having provided the light-resistant layer 2. FIG. The obtained results are shown in Table 2.

(Comparative Example 2)
It implemented on the conditions similar to Example 1 except having made the particle size of the zinc oxide particle into 0.3 micrometer. The obtained results are shown in Table 2.

(Comparative Example 3)
To a biaxially stretched film obtained under the same conditions as in Example 1, 42 parts of a benzotriazole-based ultraviolet absorber (“Udable” (registered trademark) UV-G13: manufactured by Nippon Shokubai Co., Ltd.) and a thermal crosslinking agent (“Sumijour”) “(Registered trademark) N3200: manufactured by Bayer) 2 parts and 56 parts of toluene were applied and dried by heating. At this time, the coating thickness of the light-resistant layer 2 is 10 μm. The obtained results are shown in Table 2.

(Comparative Example 4)
It implemented on the conditions similar to Example 4 except not having provided the light-resistant layer 2. FIG. The obtained results are shown in Table 2.

(Comparative Example 5)
The test was performed under the same conditions as in Example 6 except that the light-resistant layer 2 was not provided. The obtained results are shown in Table 2.

(Comparative Example 6)
The test was performed under the same conditions as in Example 6 except that the light-resistant layer 1 was not provided. However, the coating thickness of the light-resistant layer 2 was 10 μm. The obtained results are shown in Table 2.

(Comparative Example 7)
It implemented on the conditions similar to Example 1 except not having provided the light-resistant layer 1 and the light-resistant layer 2. FIG. The obtained results are shown in Table 2.

  The weather resistant resin film of the present invention can be suitably used as an outdoor member. For example, it can be used as a decorative film or a solar cell reflector.

Claims (10)

  On at least one surface of the base resin film, the light-resistant layer 1 containing metal oxide particles having an ultraviolet-absorbing ability with an average particle size of 0.1 μm or less is provided, and an organic ultraviolet absorber is further formed on the surface layer of the light-resistant layer 1 A weather-resistant resin film comprising a light-resistant layer 2 containing   The weather resistant resin film according to claim 1, wherein a light stabilizer is dispersed in the light resistant layer 1. 3. The metal oxide particles having ultraviolet absorbing ability are any one of zinc oxide, titanium oxide, cerium oxide, tungsten titanium trioxide, and strontium titanate, or a mixture thereof. Weather resistant resin film.   The base resin film is a laminated film having a structure in which layers of resin A (A layer) and layers of resin B (B layer) are alternately laminated by 10 layers or more. The weather resistant resin film according to any one of the above.   The weather resistance according to any one of claims 1 to 4, wherein the base resin film is a laminated film having a structure in which layers made of a crystalline resin and layers made of an amorphous resin are alternately laminated. Resin film.   The weather resistant resin film according to any one of claims 1 to 5, wherein the haze is 10% or less.   The weather resistant resin film according to any one of claims 1 to 6, wherein a reflectance with respect to light in any part of a wavelength range of 250 to 2500 nm is 30% or more.   The weather-resistant resin film according to any one of claims 1 to 7, wherein a reflectance with respect to light in a band of at least a wavelength of 420 to 780 nm is 40% or more.   A decorative film comprising the weatherable resin film according to claim 1.   It consists of a weather-resistant resin film in any one of Claims 1-8, The reflecting plate for solar cells characterized by the above-mentioned.